The invention relates to an electrode for electrophoretic deposition on a conductive surface.
It is known that the electrophoretic deposition of material of plastics material, for example a varnish, on metallic objects (or at least electrically conductive objects) is carried out by placing the object in the position of an electrode of a direct current source, the other electrode, connected to the other terminal of the direct current source being suitably shaped, the electrodes being placed in the electrophoresis bath.
The problem to be resolved is that of obtaining a thin deposit, typically of 2 to 20 .mu.m thickness, which is as uniform as possible on the surfaces of the object to be coated.
In the case of objects having an axis of revolution, for example cylindrical in shape, provided with a bottom and required to be coated on their inner face and in accordance with the prior art, a conductive electrode is placed on the axis of revolution of the object and preferably takes the form of a solid cylinder or of a conductive tube of circular cross-section and having the same axis as this latter. However, edge effects result such that the quantities deposited in the vicinity of the edge of the opening in the object are far greater than on the rest of the surface.